1. Field of the Invention
The invention is directed to a magnetic mechanism for a non-mechanical printer or copier device
2. Description of the Prior Art
In copying device technology and in non-mechanical fast data printers that operate on the principle of electrophotography, charge images are generated on a charge image carrier, for example on a photoconductive drum, and are subsequently inked with a black powder (toner) in a developing station. Given employment of a photoconductive drum, the toner images are subsequently transferred onto standard paper and are fixed there. As a rule, a two-component developer is used for developing, this being composed of ferromagnetic carrier particles and of toner particles. The developer mix, for example, is conducted past the charge image by means of a magnet brush arrangement, the toner particles remaining adhering to the charge image due to electrostatic forces. Such a developing station is disclosed, for example, by German patent No. 21 26 667.
Over the course of time, a developer mix can lose its triboelectric properties and it must therefore be replaced with a new developer mix at the end of its useful life. This replacement of the developer mix must be simple to carry out.
U.S. Pat. No. 3,764,208 further discloses an apparatus for removing the developer mix from a developing station of an electrophotographic apparatus. This means contains a developer drum and a mixing screw at whose end the off-take opening comprising a tube for connection of a bottle for the acceptance of the developer mix is arranged in the floor of the developing station. In order to remove the developer mix, the rotational direction of the mixing screw and of the developer drum is reversed in order to convey the developer mix to the off-take opening.
In such apparatus, there is the risk that mix can unintentionally flow out in the region of the off-take pipe. When closing and removing the bottle, there is a risk of contamination for the environment. A complete emptying is not possible since the screw and the appertaining screw channel must always have a defined distance relative to one another. The overall emptying operation lasts a relatively long time. As experience has shown, toner deposits can form at the screws which can burst off.
U.S. Pat. No. 3,930,466 further discloses a developing station for an electrophotographic apparatus wherein a magnetic mechanism is arranged between a supply region and the actual conveying region of the developing station as a closing means. The magnetic mechanism is composed of a rotatably seated permanent magnet which can be swiveled or rotated into alignment with the actual throughput channel for the developer mix. When it is swivelled in, a plug of developer mix which closes the channel is formed in the throughput channel.
The only thing possible with such a magnetic mechanism is an interruption of the developer mix in the conveying channel.